<!DOCTYPE html>
<html lang="en" xmlns:th="http://www.thymeleaf.org">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        frameset {border:0px;}
    </style>
</head>

<frameset cols="200px,*">
    <frame src="left.html">
    <frame src="center.html" name="my">
</frameset>

</html>